The Conventional method of drilling shaped holes, especially irregularly shaped holes, is the use of electric discharge machining, which works only for conductive work pieces and also requires a consumable electrode. U.S. Pat. No. 4,118,109 illustrates an optical system for controlling the direction of a beam of radiation that uses two coaxial independently rotatable wedge prisms to steer the beam within a cone of predetermined angle. This system does not permit independent control of the beam spot location and angle. This patent also does not refer to focusing the optical beam.
U.S. Pat. No. 4,079,230 illustrates a system for scanning an optical beam across a work piece by using a pair of wedge prisms rotating in opposite directions at the same speed to scan the beam in a straight line across the work piece.